This invention relates generally to electrical connectors and more particularly to sealed electrical connectors that pass through a housing that is filled with a liquid, such as a automotive transmission housing that is filled with transmission fluid.
Electronically controlled transmissions require electrical power and signal communication between exterior electrical devices and electrical components inside the transmission housing which is achieved by electrical cables passing through a hole in the transmission housing. The transmission housings are filled with transmission fluid which makes it difficult to seal the hole because the internal geometry of the electric cables inside the housing produce a wicking and/or capillary effect that brings the transmission fluid to the seal faces.
Presently, electric cables are passed into the transmission housing through a hole in a wall of the transmission housing by a sealed electrical connector system. This system comprises a "pass-through" electrical connector that is mounted in the hole in the transmission housing wall and contains male terminals of the contact blade type. The male terminals are attached to the ends of the electric cables inside the transmission housing with their flat and relatively wide contact blades positioned outside the transmission housing. An external electrical connector that contains mating female terminals attached to the ends of the external electrical cables is then simply plugged on the "pass-through" electrical connector to interconnect the internal and external cables.
The transmission wall hole is sealed off by a rubber O-ring seal carried by the pass-through connector. The pass-through electrical connector itself is sealed by two serially arranged seals. First, a cable seal seals around the internal electric cables at the cable end of the connector body that is inside the transmission housing. Then a face seal seals around the flat wide contact blades at the mating end of the connector body that is outside the transmission housing.
This present system is very difficult to seal effectively even though it has two serially arranged seals because of the wicking and/or capillary action of the electric cables inside the fluid filled transmission housing. Due to this wicking and/or capillary action the transmission fluid travels along the interior of the electric cables and tends to leak through the cable seal into the terminal cavity of the pass-through connector, travel along the terminal and then leak through the face seal to the exterior of the transmission housing. Fluid tight sealing at the face seal is particularly difficult to achieve because the flat wide contact blades of the male terminals protrude through the face seal for insertion into the mating female terminals when the external electrical connector is plugged on.